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Maker Advisor

Best Tools and Gear for Makers

UM24/UM24C USB Meter – Voltage, Power and Current Tester with Color LCD by RUIDENG – Review

March 9, 2020 By Rui Santos

UM24 or UM24C USB Meter Voltage and Current Tester with Color LCD by RUIDENG Review

The UM24/UM24C USB Meter by RUIDENG allows you to measure voltage, current and power consumption directly from any USB device. It’s like a multimeter for USB type devices. The UMXX USB Meter has been in our radar for a while, but we finally got it and we’ll review it in this article.

UM24 vs UM24C

The UM24 USB meter comes in two different versions: the UM24 and UM24C. The UM24C is slightly more expensive, because it has a built-in Bluetooth board that you can use to connect to an Android App or Windows PC software.

Banggood - UM24 USB Voltage Current Power Meter/Tester

Banggood - UM24 USB Voltage Current Power Meter/Tester

★★★★★
$18.05
$10.99
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as of January 22, 2025 5:32 pm
Banggood - UM24C USB Voltage Current Power Meter/Tester (with Bluetooth communication)

Banggood - UM24C USB Voltage Current Power Meter/Tester (with Bluetooth communication)

★★★★★
$22.05
$14.99
 out of stock
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Banggood.com
as of January 22, 2025 5:32 pm

Product Details and Specifications

  • Voltage range: 4.50 – 24.00V
  • Voltage resolution: 0.01V
  • Voltage accuracy: ±(0.2%+1 digit)
  • Current range: 0.0 – 3.000A
  • Current resolution: 0.001A
  • Current accuracy: ±(0.8%+3 digit)
  • Capacity accumulation range: 0 – 99999mAh
  • Energy accumulation range: 0 – 99999mWh
  • Load impedance range: 1.5 – 9999.9Ω
  • Temperature range: -10ºC~100ºC / 0ºF~200ºF
  • Temperature error: ±3ºC/±6ºF
  • Screen brightness: 0-5 level
  • Auto screen off time: 1 – 9 minutes
  • Voltage graphing range: 4.5 – 24.0V
  • Current graphing range: 0.0 – 3.0A
  • Screen: 1.44 inch color LCD display
  • Quick charge recognition mode: QC2.0/QC3.0
  • Refresh rate: 2Hz

UM24(C) vs UM34(C) vs UM25(C)

There are a few types of UMXX devices (the modules with a C in front of their name support Bluetooth communication). Here’s the main specs and differences:

Product modelUM24(C)UM34(C)UM25(C)
Image
USB portUSB 2.0USB 3.0USB 2.0
Expansion portMicro USB Type BMicro USB Type CMicro USB Type C
Voltage range4.50 – 24.00V4 – 24.00V4.50 – 24.000V
Voltage resolution 0.01V0.01V0.001V
Current range0.0 – 3.000A0.0 – 4.000A0.0 – 5.000A
Current resolution0.001A0.001A0.0001A
Quick charge modeQC2.0, QC3.0QC2.0, QC3.0, Apple, Android DCP, SamsungQC2.0, QC3.0, Apple, Android DCP, Samsung
Where to buyBanggoodBanggoodBanggood

For our needs, we’ve decided that the UM24C was more than enough, but if you need to work with USB 3.0 or detect a different type of Quick Charge mode, you can get a UM34(C) or UM25(C).

Where to Buy UM24?

eBay - UM24C USB Voltage Current Power Meter/Tester
eBay - UM24C USB Voltage Current Power Meter/Tester
eBay - UM24C USB Voltage Current Power Meter/Tester
$19.99
out of stock
BUY NOW
eBay
Banggood - UM24C USB Voltage Current Power Meter/Tester (with Bluetooth communication)
Banggood - UM24C USB Voltage Current Power Meter/Tester (with Bluetooth communication)
Banggood - UM24C USB Voltage Current Power Meter/Tester (with Bluetooth communication)
$14.99
$22.05
out of stock
BUY NOW
Banggood.com
Amazon.com - UM24C USB Voltage Current Power Meter/Tester
Amazon.com - UM24C USB Voltage Current Power Meter/Tester
Amazon.com - UM24C USB Voltage Current Power Meter/Tester
$19.50
out of stock
2 new from $19.50
as of January 27, 2025 11:46 am
BUY NOW
Amazon.com

Where to Buy UM24C (with Bluetooth Board)

Amazon.com - UM24 or UM24C USB Voltage Current Power Meter/Tester
Amazon.com - UM24 or UM24C USB Voltage Current Power Meter/Tester
Amazon.com - UM24 or UM24C USB Voltage Current Power Meter/Tester
$22.99
in stock
2 new from $22.99
as of January 27, 2025 11:46 am
BUY NOW
Amazon.com
Banggood - UM24 USB Voltage Current Power Meter/Tester
Banggood - UM24 USB Voltage Current Power Meter/Tester
Banggood - UM24 USB Voltage Current Power Meter/Tester
$10.99
$18.05
out of stock
BUY NOW
Banggood.com
eBay - UM24 USB Voltage Current Power Meter/Tester
eBay - UM24 USB Voltage Current Power Meter/Tester
eBay - UM24 USB Voltage Current Power Meter/Tester
$12.49
out of stock
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eBay

If you decide to get the UM24C that comes with a Bluetooth board, you can download the PC software or Android App:

  • PC software supports Windows 7 and above.
  • Android phone supports Android 5.0 and above (compatible with 3 languages: English, Chinese and Russian) .
  • You can open this link to download the PC software, Android .apk, and instructions from the official source: Mediafire download folder.

Note: the preceding download link sends you to the official manufacturer source and we haven’t tested that software. In our opinion, we think the color LCD displays everything that we need, but we like to have the option to use Bluetooth in the future.

Unboxing USB Tester

The UM24/UM24C USB Tester comes in a neat aluminium case well packed with a dense foam which holds the USB meter tightly.

UM24 UM24C USB Voltage Current Charger Tester RUIDENG box enclosure

Inside the enclosure, it only has the USB meter – there are no instructions or accessories.

UM24 UM24C USB Voltage Current Charger Tester RUIDENG

USB Input

This board comes with two USB input ports. You can either power the USB meter with a USB B input.

UM24 UM24C USB Voltage Current Charger Tester RUIDENG USB Input

Or you can use the Micro USB Type B port to power it:

UM24 UM24C USB Voltage Current Charger Tester Micro USB Input

USB Output

On the other side of the board, you have a female USB B port. Here you connect the device you want to get power measurements.

UM24 UM24C USB Voltage Current Charger Tester RUIDENG USB Output

Buttons

This board also has 2 buttons on each side. These buttons are used to access the menus and change the settings. The two buttons on the bottom allow you to go to the Help menu or change to the Next interface.

UM24 UM24C USB Voltage Current Charger Tester buttons

There are also two other buttons on top that allow you to rotate the screen orientation with a long press.

UM24 UM24C USB Voltage Current Charger Tester 2 buttons

How to Use UM24 / UM24C USB Meter

For this demonstration, we’ll be powering the UM24C USB Meter with a power bank in the USB B input and use a USB cable to power an ESP32 board. When you first apply power, you’ll see the next loading screen.

UM24 UM24C USB Voltage Current Charger Tester RUIDENG loading screen

These USB Meters features 7 menus:

  1. Main Interface
  2. Quick Charger Recognition
  3. Charging Recording
  4. Wire Impedance Measurement
  5. Voltage Graph
  6. Current Graph
  7. Settings
UM24 UM24C USB Tester Menus User Interface UI

1. Main Menu

This is the main menu that appears and it displays: voltage, current, temperature (in Celsius or Fahrenheit), group, power consumption, cable impedance and more.

UM24 UM24C USB Voltage Current Charger Tester RUIDENG LCD color display screen

Help Menu

When you open the Help menu, you’ll see what you can do in that specific screen. For example, with a long press you can either rotate the screen, clear the data group or change the data group.

UM24 UM24C USB Tester RUIDENG help menu long press rotate screen

2. Quick Charger Recognition

In this menu, you can detect the type of Quick Charge mode. In this example I’m using a power bank and as you can see it says “Mode Unknown“.

UM24 UM24C USB Voltage Current Charger Tester RUIDENG LCD color display screen menu 2

If I use my smartphone charger it detects properly as “Mode QC2.0“.

3. Charging Recording

You can define a current threshold that when triggered will record the time, and power consumption during a charge.

UM24 UM24C USB Tester RUIDENG power usage consumption

4. Wire Impedance Measurement

You can get the wire impedance measurement:

UM24 UM24C USB Tester input output

5. Voltage Graph/Plot

In this example, we’re measuring the voltage that an ESP32 DO IT board is using while connected to Wi-Fi and hosting a web server. As you can see, it’s using approximately 5.08V.

UM24 UM24C USB Tester RUIDENG voltage graph plot

6. Current Graph/Plot

In terms of current, the ESP32 is consuming around 0.07A:

UM24 UM24C USB Tester RUIDENG current graph plot

7. Change Settings

If you hold the bottom-right button, you can change the USB meter settings:

  • Auto screen off time from 1 minute to 9 minutes
  • Screen brightness between a 0 and 5 level
  • Temperature in Celsius or Fahrenheit (the temperature range is -10ºC~100ºC / 0ºF~200ºF with an error of ±3ºC/±6ºF)
UM24 UM24C USB Tester RUIDENG change settings temperature timer brightness

Wrapping Up

The USB meter can be a great addition to your electronics lab. It provides an easy way to measure power consumption (and other related measurements) of devices that support a USB port. In my case, the UM24 USB tester is very handy to give me an idea of power consumption of my ESP32 and ESP8266 projects.

Banggood - UM24 USB Voltage Current Power Meter/Tester
Banggood - UM24 USB Voltage Current Power Meter/Tester
Banggood - UM24 USB Voltage Current Power Meter/Tester
$10.99
$18.05
out of stock
BUY NOW
Banggood.com
Banggood - UM24C USB Voltage Current Power Meter/Tester (with Bluetooth communication)
Banggood - UM24C USB Voltage Current Power Meter/Tester (with Bluetooth communication)
Banggood - UM24C USB Voltage Current Power Meter/Tester (with Bluetooth communication)
$14.99
$22.05
out of stock
BUY NOW
Banggood.com

So, to conclude, the UM24 USB meter board is very well designed and versatile. I think it is a great tool for the average maker or electronics hobbyist.

We have other reviews that you may like:

  • Best Multimeters under $50 – Buying Guide and Comparison
  • Best Low Cost Multimeter? ANENG AN8002 Multimeter Review
  • XR2206 Function Generator DIY Kit Review
  • DIY Transistor Tester Kit Review – Hiland M12864

Thanks for checking out this review, we’ll have more very soon! Make sure you subscribe our newsletter.


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We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites. We also participate in programs from Banggood, eBay, Aliexpress, ShareASale, and other sites. Maker Advisor is compensated for referring traffic and business to these companies (read more).